<!DOCTYPE html>

<html>

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

    <title>💗</title>
    <style>
        canvas {
            position: absolute;
            left: 0;
            top: 0;
            width: 100%;
            height: 100%;
            background-color: rgba(0, 0, 0, .2);
        }
    </style>
</head>

<body>

    <canvas id="heart" width="1920" height="947"></canvas>
    <script>
        window.requestAnimationFrame =
            window.__requestAnimationFrame ||
            window.requestAnimationFrame ||
            window.webkitRequestAnimationFrame ||
            window.mozRequestAnimationFrame ||
            window.oRequestAnimationFrame ||
            window.msRequestAnimationFrame ||
            (function () {
                return function (callback, element) {
                    var lastTime = element.__lastTime;
                    if (lastTime === undefined) {
                        lastTime = 0;
                    }
                    var currTime = Date.now();
                    var timeToCall = Math.max(1, 33 - (currTime - lastTime));
                    window.setTimeout(callback, timeToCall);
                    element.__lastTime = currTime + timeToCall;
                };
            })();
        window.isDevice = (/android|webos|iphone|ipad|ipod|blackberry|iemobile|opera mini/i.test(((navigator.userAgent || navigator.vendor || window.opera)).toLowerCase()));
        var loaded = false;
        var init = function () {
            if (loaded) return;
            loaded = true;
            var mobile = window.isDevice;
            var koef = mobile ? 0.5 : 1;
            var canvas = document.getElementById('heart');
            var ctx = canvas.getContext('2d');
            var width = canvas.width = koef * innerWidth;
            var height = canvas.height = koef * innerHeight;
            var rand = Math.random;
            ctx.fillStyle = "rgba(0,0,0,1)";
            ctx.fillRect(0, 0, width, height);

            var heartPosition = function (rad) {
                //return [Math.sin(rad), Math.cos(rad)];
                return [Math.pow(Math.sin(rad), 3), -(15 * Math.cos(rad) - 5 * Math.cos(2 * rad) - 2 * Math.cos(3 * rad) - Math.cos(4 * rad))];
            };
            var scaleAndTranslate = function (pos, sx, sy, dx, dy) {
                return [dx + pos[0] * sx, dy + pos[1] * sy];
            };

            window.addEventListener('resize', function () {
                width = canvas.width = koef * innerWidth;
                height = canvas.height = koef * innerHeight;
                ctx.fillStyle = "rgba(0,0,0,1)";
                ctx.fillRect(0, 0, width, height);
            });

            var traceCount = mobile ? 20 : 50;
            var pointsOrigin = [];
            var i;
            var dr = mobile ? 0.3 : 0.1;
            for (i = 0; i < Math.PI * 2; i += dr) pointsOrigin.push(scaleAndTranslate(heartPosition(i), 210, 13, 0, 0));
            for (i = 0; i < Math.PI * 2; i += dr) pointsOrigin.push(scaleAndTranslate(heartPosition(i), 150, 9, 0, 0));
            for (i = 0; i < Math.PI * 2; i += dr) pointsOrigin.push(scaleAndTranslate(heartPosition(i), 90, 5, 0, 0));
            var heartPointsCount = pointsOrigin.length;

            var targetPoints = [];
            var pulse = function (kx, ky) {
                for (i = 0; i < pointsOrigin.length; i++) {
                    targetPoints[i] = [];
                    targetPoints[i][0] = kx * pointsOrigin[i][0] + width / 2;
                    targetPoints[i][1] = ky * pointsOrigin[i][1] + height / 2;
                }
            };

            var e = [];
            for (i = 0; i < heartPointsCount; i++) {
                var x = rand() * width;
                var y = rand() * height;
                e[i] = {
                    vx: 0,
                    vy: 0,
                    R: 2,
                    speed: rand() + 5,
                    q: ~~(rand() * heartPointsCount),
                    D: 2 * (i % 2) - 1,
                    force: 0.2 * rand() + 0.7,
                    f: "hsla(240," + ~~(40 * rand() + 60) + "%," + ~~(60 * rand() + 20) + "%,.3)",   //修改颜色
                    trace: []
                };
                for (var k = 0; k < traceCount; k++) e[i].trace[k] = { x: x, y: y };
            }

            var config = {
                traceK: 0.4,
                timeDelta: 0.01
            };

            var time = 0;
            var loop = function () {
                var n = -Math.cos(time);
                pulse((1 + n) * .5, (1 + n) * .5);
                time += ((Math.sin(time)) < 0 ? 9 : (n > 0.8) ? .2 : 1) * config.timeDelta;
                ctx.fillStyle = "rgba(0,0,0,.1)";
                ctx.fillRect(0, 0, width, height);
                for (i = e.length; i--;) {
                    var u = e[i];
                    var q = targetPoints[u.q];
                    var dx = u.trace[0].x - q[0];
                    var dy = u.trace[0].y - q[1];
                    var length = Math.sqrt(dx * dx + dy * dy);
                    if (10 > length) {
                        if (0.95 < rand()) {
                            u.q = ~~(rand() * heartPointsCount);
                        } else {
                            if (0.99 < rand()) {
                                u.D *= -1;
                            }
                            u.q += u.D;
                            u.q %= heartPointsCount;
                            if (0 > u.q) {
                                u.q += heartPointsCount;
                            }
                        }
                    }
                    u.vx += -dx / length * u.speed;
                    u.vy += -dy / length * u.speed;
                    u.trace[0].x += u.vx;
                    u.trace[0].y += u.vy;
                    u.vx *= u.force;
                    u.vy *= u.force;
                    for (k = 0; k < u.trace.length - 1;) {
                        var T = u.trace[k];
                        var N = u.trace[++k];
                        N.x -= config.traceK * (N.x - T.x);
                        N.y -= config.traceK * (N.y - T.y);
                    }
                    ctx.fillStyle = u.f;
                    for (k = 0; k < u.trace.length; k++) {
                        ctx.fillRect(u.trace[k].x, u.trace[k].y, 1, 1);
                    }
                }
                ctx.fillStyle = "rgba(255,255,255,1)";
                for (i = u.trace.length + 13; i--;) ctx.fillRect(targetPoints[i][0], targetPoints[i][1], 2, 2);

                window.requestAnimationFrame(loop, canvas);
            };
            loop();
        };

        var s = document.readyState;
        if (s === 'complete' || s === 'loaded' || s === 'interactive') init();
        else document.addEventListener('DOMContentLoaded', init, false);
    </script>

</body>

</html>